The goal of this chapter is to introduce briefly certain products and technologies that might gain increasing importance in building Web applications.
It is difficult to predict the future, but a safe prediction is that new products and technologies as well as new combinations and packaging of products and technologies will emerge. The Web has evolved from a medium in which scientists could share information, to a channel for complex interactions involving the use of databases. As the applications become more complex, the application developers will look for improved tools, and software developers will attempt to invent new solutions.
This chapter will describe a collection of products and issues. A principle one is eXtensible Markup Language (XML), which is a component of other technologies cited here, including Web Services, Wireless Markup Language, and VoiceXML. The Examples section will show you a use of XML with PHP. The Reflection section will guide you in the use of the Exercises section to do your own research on these issues.